Patent GB-1064675-A (GB)
Title: Improvements in nozzles for discharge of compressible fluid
Inventor: LANE RAYMOND JOHN
IPC: F02K1/06
Filed: 1962-11-26
Abstract: 1,064,675. Jet propulsion nozzles. BRISTOL SIDDELEY ENGINES Ltd. Nov. 19, 1963 [NOV. 26, 1962], No.40605/62. Heading F1J. A convergent-divergent nozzle for the discharge of a gas into an ambient atmosphere comprises an outer wall enclosing a duct with an open discharge end, and at least one vane which projects into the duct from the outer wall, each vane having two mutually divergent flanks each of which terminates downstream at a trailing edge spaced upstream from the open discharge end of the duct the arrangement being such that in operation streams of fluid break away from the vane at the trailing edges and portions of the streams form a circulatory flow system, the system having a static pressure higher than ambient atmospheric pressure and having mutually convergent boundaries which define divergent surfaces with respect to the main gas flow. In Figs. 1 and 2 is shown a nozzle 11 of rectangular section comprising upper and lower walls 47 and side walls 48, a wedge-shaped vane 15 being disposed within the nozzle with its apex 16 upstream and its flat base portion downstream. The vane 15 forms two convergent ducts 13, 14 and a region of circulatory flow 17 at a pressure above ambient atmospheric pressure is formed downstream of the vane, boundaries 18 of this region forming virtual divergent nozzle walls whereby the gas stream is accelerated to a velocity in excess of Mach 1. A ram jet duct of rectangular crosssection is shown in Figs. 3 and 4 and comprises upper and lower walls 92, 93 and side walls, the walls 92, 93 being divergent at the upstream end to form a subsonic diffuser 94. Disposed within the duct is a plurality of vanes 96 each formed by a pair of flanks 97, 98 which are fixed and define an opening 104 at the upstream end for flow of cooling air. At the downstream ends of the fixed flanks 97, 98 are mounted flank portions 99, 100 which are pivotally mounted on shafts 99a, 100a, the flank portions constituting continuations of the flanks 97, 98. The bases of the vanes are formed by parts 99c, 100c and by fixed parts 102, the vane at the upper part of Fig. 4 being shown in its position of minimum width, and that at the lower part of the Figure in its position of maximum width. The vane portions 99, 100 are adjustable by means of a rod 110 having screwed portions of opposite hand engaging nuts 108, 109 which are connected to links 106, 107 secured to the shafts 99a, 100a. Fuel distribution and flame holding devices 111, 112 are provided. In Figs. 5 and 7 is shown a nozzle 19 of circular form and a centre body 20 which together define an annular passage 21. Eight wedge-shaped vanes 15 are disposed radially across the annular passage, the vanes having convex-shaped flanges 22 and concave-shaped bases 23, regions of circulatory flow being indicated at 17 and 26 downstream of the vanes 15 and of the centre body 20. The invention is shown applied to a gas turbine jet engine of the by-pass type in Fig. 8 in which the downstream end of the turbine exhaust duct is indicated at 32 and the downstream end of the by-pass duct at 33, the duct 32 being constituted by an inner wall 37 and an intermediate wall 35, while the duct 33 is constituted by the intermediate wall 35 and an outer wall 34. A pod or fairing 30 is disposed around the outer wall 34 and in effect forms part of the outer wall. The engine is supported by means of a strut 31. The walls 34, 35, 37 are of octagonal form with rounded corners as seen in Fig. 9, the intermediate wall 35 being of hollow form to permit flow of cooling air. The inner wall 37 defines a centre body 36 having a flat downstream end wall 39. A series of openings 43 are provided in the fairing 30, an axially-movable cylindrical valve member 44 having corresponding openings 45 being disposed to co-operate with the openings 43 so as either to allow or to prevent flow of ambient air through the openings 43. Series of vanes 51 and 52 are disposed in the passages 33 and 32 respectively, the vanes being shown in section in Figs. 10 and 11. The vanes each comprise a fixed leading edge portion 53 and flank portions 54, 55 pivotally mounted on shafts 56, 57, the flank portions having wall portions 54b, 55b towards their trailing edges, wall portions 54b, 55b co-operating with a fixed wall 58 to define the base of the vane. The position of the flank portions 54, 55 of the vanes in the by-pass duct 33 may be varied by means of a motor 71 acting through a shaft 70 and rack and pinion devices which move ring members 66, 67, the ring members being connected by means of levers 62, 63 to the flank portions 54, 55. The positions of the flank portions of the vanes 52 in the inner annular duct 32 are controlled in similar manner. Combustion equipment is provided in the by-pass duct 33 upstream of the portion shown.